CN102523666A - High-efficiency LED (Light Emitting Diode) driving circuit and driving method thereof - Google Patents
High-efficiency LED (Light Emitting Diode) driving circuit and driving method thereof Download PDFInfo
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Abstract
The invention discloses a high-efficiency LED (Light Emitting Diode) driving method, which is used for driving an LED device. The high-efficiency LED driving method comprises the steps of: receiving an alternating-current input voltage, and carrying out detection to obtain an absolute value of the alternating-current input voltage; receiving a direct-current bus voltage by a power switch and generating a driving voltage and driving current so as to drive the LED device, wherein the direct-current bus voltage is obtained by rectifying the alternating-current input voltage; adjusting a first reference voltage according to the driving current; sampling the driving voltage of the LED device; comparing the absolute value of the alternating-current input voltage and the summation of the driving voltage and the first reference voltage; when the absolute value of the alternating-current input voltage is more than the summation of the driving voltage and the first reference voltage, switching off the power switch; and when the absolute value of the alternating-current input voltage is more than the summation of the driving voltage and smaller than the summation of the driving voltage and the first reference voltage, switching on the power switch so as to generate an output current, wherein the absolute value of the output current is matched with the driving current required by the LED device.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to a driving circuit applied to an LED device and a driving method thereof.
Background
With continuous innovation and rapid development of the lighting industry and increasing importance of energy conservation and environmental protection, LED lighting is rapidly developing as a revolutionary energy-saving lighting technology. However, since the brightness of an LED lamp is related to the light output intensity parameter, it is proportional to its current and forward voltage drop, and changes with temperature. Therefore, the driving of the LED requires a constant current power supply to ensure the safety of the LED and achieve an ideal light emitting intensity. It can be seen that it is important to choose the correct LED drive. Without good matching of the LED driving power supply, the advantages of LED illumination cannot be reflected.
In the prior art, two types of power regulators are generally used as LED drivers, one being a linear regulator and the other being a switching regulator. Referring to fig. 1A, a schematic block diagram of a prior art LED driver using a linear regulator is shown, which includes a power switch M1, an error amplifier EA1 and a detection resistor Rsense1. Detecting resistance Rsense1The output current of the power switch M1 is sampled and compared with a reference value VREF1Performing an error amplification operation by the error amplifier EA1 to obtain an error signal Verror1. The power switch M1 receives the DC bus voltage VbusAnd said error signal Verror1To produce a substantially constant output voltage and output current to drive the LED device. Therefore, the LED driver adopting the linear regulator has the advantages of relatively simple circuit structure, fewer components and lower cost; however, the efficiency of such LED drivers is low. For example, the input ac voltage ranges from 90V to 265V, and the dc bus voltage obtained through the rectifier bridge ranges from about 120V to 375V. Therefore, the driving voltage of the LED device cannot be larger than the minimum bus voltage (i.e. 120V), and the voltage is displayedHowever, for a 375V dc bus voltage (ac 265V), the resulting power loss is very large, and the efficiency will be less than 35%.
Referring to fig. 1B, a schematic block diagram of a prior art LED driver using a switching regulator is shown; the power switch M2, the output inductor L1 and the output diode D1 form a voltage reduction type topological structure; detecting resistance Rsense2Sampling the current flowing through the LED device and comparing the sampled current with a reference value VREF2Performing an error operation to obtain an error signal Verror2(ii) a A control and drive circuit receives the error signal Verror2To generate a corresponding driving signal to drive the power switch M2 to be periodically turned on or off, thereby outputting a substantially constant output voltage and output current to drive the LED device. Switching regulators can theoretically achieve near 100% operating efficiency without taking into account conduction losses in the power switches and magnetic elements (inductors). However, the operating frequency of the switching regulator is high, and therefore an EMI filter circuit is indispensable. Therefore, compared to a linear regulator, the switching regulator has a larger number of components, a larger size, and a relatively higher cost.
Disclosure of Invention
In view of the above, the present invention provides a high efficiency LED driving circuit, which only uses one power switch; selectively outputting current according to the numerical relation between the input voltage and the driving voltage; when the input voltage is higher, no current is output; when the input voltage is small, a certain current is output to drive the LED device.
According to an embodiment of the present invention, a high efficiency LED driving method for driving an LED device includes:
receiving an alternating current input voltage, and detecting to obtain an absolute value of the alternating current input voltage;
a power switch receives a direct current bus voltage and generates a driving voltage and a driving current to drive the LED device; the direct current bus voltage is obtained by rectifying the alternating current input voltage;
generating a variable first reference voltage according to a present driving current and a desired driving current of the LED device;
sampling a driving voltage of the LED device;
comparing the absolute value of the AC input voltage with the sum of the drive voltage and the first reference voltage;
turning off the power switch when the absolute value of the alternating current input voltage is greater than the sum of the driving voltage and a first reference voltage;
when the absolute value of the alternating current input voltage is larger than the driving voltage and smaller than the sum of the driving voltage and a first reference voltage, the power switch is switched on to generate an output current; the average value of the output current matches the desired drive current.
Further, the generating of the first reference voltage further includes:
sampling the current driving current of the LED device;
calculating an error between the present drive current and the desired drive current to obtain an error control signal;
when the present drive current is less than the desired drive current, the error control signal adjusts the first reference voltage to increase the first reference voltage;
the error control signal adjusts the first reference voltage to decrease the first reference voltage when the present drive current is greater than the desired drive current.
Preferably, the generating of the first reference voltage includes:
controlling a controllable current source according to the error control signal;
and charging a resistor by using the controllable current source, so that the voltage at two ends of the resistor is used as the first reference voltage.
Preferably, the LED driving method further includes limiting a conduction current of the power switch.
Preferably, the LED driving method includes shaping a waveform of an on-current of the power switch.
A high efficiency LED driving circuit according to an embodiment of the present invention includes a power switch for receiving an AC input voltage and generating a driving voltage and a driving current to drive an LED device, including,
the alternating voltage detection circuit is used for receiving the alternating input voltage and obtaining the absolute value of the alternating input voltage;
a feedback control circuit for generating a variable first reference voltage based on the received drive current and a desired drive current for the LED device;
the first comparison circuit is respectively connected with the alternating current voltage detection circuit and the feedback control circuit and is used for comparing the absolute value of the received alternating current input voltage with the sum of the first reference voltage and the driving voltage;
a first power end of the power switch receives a direct-current bus voltage, and the direct-current bus voltage is obtained by rectifying the alternating-current input voltage through a rectifier bridge; the second power end is connected to an output capacitor; the control end is connected to the first comparison circuit;
when the absolute value of the alternating-current input voltage is larger than the sum of the driving voltage and the first reference voltage, the first comparison circuit controls the power switch to be switched off;
when the absolute value of the alternating-current input voltage is larger than the driving voltage and smaller than the sum of the driving voltage and the first reference voltage, the first comparison circuit controls the power switch to be conducted, so that an output current is generated, and the average value of the output current is ensured to be matched with the expected driving current.
Preferably, the feedback control circuit comprises a detection circuit, an error amplifier and a first reference voltage generation circuit; wherein,
the detection circuit is connected between an output capacitor and the LED device in series to sample the current driving current;
the error amplifier is used for calculating the error between the received current driving current and the expected driving current so as to obtain an error control signal;
the first reference voltage generating circuit correspondingly generates the changed first reference voltage according to the received error control signal, and inputs the changed first reference voltage and the driving voltage to the first comparison circuit after being superposed.
Preferably, the first reference voltage generating circuit comprises a controllable current source and a resistor;
the error control signal is input to the controllable current source to control the output current of the controllable current source; the voltage of the output current of the controllable current source on a resistor is used as the first reference voltage.
Preferably, the LED driving circuit further includes a current limiting circuit connected between the power switch and the rectifier bridge to limit the on-current of the power switch.
Preferably, the LED driving circuit further includes a waveform shaping circuit connected between the power switch and the rectifier bridge to shape a waveform of the on-current of the power switch to reduce a harmonic component thereof.
According to the high-efficiency LED driving circuit and the driving method disclosed by the invention, the current is selectively output according to the numerical relation between the input voltage and the driving voltage so as to realize the maximum working efficiency; meanwhile, the main circuit has a relatively simple structure, does not need a complex electromagnetic interference filtering circuit any more, and has relatively better optimized size and cost.
Drawings
FIG. 1A is a schematic block diagram of an LED driver employing a linear regulator of the prior art;
FIG. 1B is a schematic block diagram of an LED driver employing a prior art switching regulator;
FIG. 2A is a schematic block diagram of a high efficiency LED driver circuit according to one embodiment of the present invention;
FIG. 2B is a waveform diagram illustrating the operation of the LED driving circuit shown in FIG. 2A according to the present invention;
FIG. 3 is a schematic block diagram of a high efficiency LED driver circuit according to another embodiment of the present invention;
fig. 4 is a flow chart of a high-efficiency LED driving method according to a preferred embodiment of the present invention.
Detailed Description
Several preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to only these embodiments. The invention is intended to cover alternatives, modifications, equivalents, and alternatives that may be included within the spirit and scope of the invention. In the following description of the preferred embodiments of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention, and it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
The following describes an implementation of the LED driving circuit according to the present invention in detail with reference to specific embodiments.
Referring to fig. 2A, a schematic block diagram of a high efficiency LED driving circuit according to a first embodiment of the present invention is shown. In this embodiment, the LED driving circuit includes a power switch SMOutput capacitance CoutA first comparison circuit 201, a feedback control circuit 202, and an input ac voltage detection circuit 203; wherein,
the power switch SMThe first power terminal is coupled to the DC bus voltage VbusA first terminal (input voltage), a second power terminal coupled to a first terminal of an LED device, the DC bus voltage VbusThe voltage is obtained by rectifying an input alternating voltage through a rectifier bridge;
the output capacitor CoutConnected in parallel with the LED arrangement and having a first end coupled to a power switch SMA second terminal coupled to the dc bus voltage VbusA second end of (a);
the input ac voltage detection circuit 203 is used for receiving an input ac voltage and obtaining an absolute value V of the input ac voltageab；
The feedback control circuit 202 receives a driving current I representing the current LED deviceLEDFirst control signal IsenseAnd a second reference voltage V characterizing the desired drive currentref2To generate the adjustable first reference voltage Vref1；
A first input terminal of the first comparing circuit 201 is connected to the ac input voltage detecting circuit 203 to receive the absolute value V of the ac input voltageabA second input terminal for receiving the driving voltage V of the LED deviceLEDAnd the first reference voltage Vref1The sum of (1); an output terminal of the first comparing circuit 201 is coupled to the power switch SMTo utilize the driving signal VdriveControlling the power switch SMThe state of (1);
when the absolute value of the AC input voltageVabGreater than the drive voltage VLEDAnd said first reference voltage Vref1When the voltage is summed, the first comparison circuit 201 controls the power switch SMTurning off;
when the absolute value of the AC input voltage is greater than the driving voltage VLEDBut less than said driving voltage VLEDAnd said first reference voltage Vref1When sum is over, the power switch S is turned onMThereby generating an output current IoutAnd to ensure that the average value of the output current matches the desired drive current.
The following describes the operation of the LED driving circuit shown in fig. 2A according to the present invention in detail with reference to the waveform diagram of the operation of the LED driving circuit shown in fig. 2A shown in fig. 2B.
When the absolute value V of the AC input voltageabGreater than the drive voltage VLEDAnd said first reference voltage Vref1When the voltage is summed, the first comparison circuit 201 controls the power switch SMOff, no output current;
when the absolute value V of the AC input voltageabGreater than the drive voltage VLEDBut less than said driving voltage VLEDAnd said first reference voltage Vref1When sum is over, the power switch S is turned onMTo generate a certain output current Iout(ii) a Within half working period T/2, the current I is outputoutOf 2 x t1(ii) a Since the adjustable first reference voltage characterizes the difference between the current LED drive current and the desired drive current, the first reference voltage V is adjusted byref1Adjustment of the value, ensuring power switch SMOutput current I ofoutThe average value of (d) matches the desired drive current.
When the DC bus voltage VbusIs less than the driving voltage VLEDWhen the LED drive circuit does not work, namely the power switch S at the momentMIs zero.
With the LED driving circuit according to the present invention shown in fig. 2A, when the dc bus voltage, i.e., the input voltage, is small, the power switch SMOutputting a certain output current within a certain time interval; since the time interval represents the difference between the current LED driving current and the desired driving current, it can be ensured that the average value of the output current matches the required driving current to meet the requirements for driving the LED device; and when the direct current bus voltage is larger, the power switch is turned off, so that the working efficiency is greatly improved compared with the LED driver adopting a linear regulator in the prior art.
For example, assume that the driving voltage V of the LED deviceLED120V, peak value V of dc bus voltagepkThe driving current of the LED device is I (240V)LED＝100mA；
Then for the LED driver using the linear regulator (as shown in fig. 1A), the working efficiency is:
for the LED driving circuit using the LED driving method of the present invention, assuming that the first reference voltage has a value of 2.4V, the driving current I is setLEDCan be approximately expressed as:
i.e. so as to drive the current ILEDCan be approximately expressed as:
input power PinCan be approximately expressed as:
therefore, the LED driving circuit adopting the LED driving method of the invention has the working efficiency as follows:
η2＝VLED×ILED/Pin＝VLED/(VLED+Vref1/2)≈99％ (5)
due to the first reference voltage Vref1Relative to the drive voltage VLEDThe value of (c) is small and therefore negligible, so that the operating efficiency can be approximately up to 100%, obtaining an efficiency much higher than that of the LED driving methods of the prior art.
Optimally, in order to prevent the conducting current of the power switch from being too large, the power switch S can be arrangedMAnd a current limiting circuit is connected in series between the rectifier bridge and the power switch so as to limit the conducting current of the power switch.
Optimally, in order to reduce harmonic components in the on-current of the power switch, it is possible to reduce harmonic components in the power switch SMAnd a waveform shaping circuit is connected in series between the rectifier bridge and the power switch to shape the waveform of the conduction current of the power switch.
Those skilled in the art will appreciate that the current limiting circuit and the waveform shaping circuit may be any suitable circuit configuration.
With the LED driving circuit shown in FIG. 2A, the power switch S is adoptedMCan be a MOSFET transistor or other suitable switching tube; the feedback control circuit 303 may be any suitable form of control circuit structure.
Referring to fig. 3, a schematic block diagram of an LED driving circuit according to a second embodiment of the present invention is shown. On the basis of the LED driving circuit shown in fig. 2A, in this embodiment, the LED driving circuit includes a power switch SMOutput capacitance CoutA first comparison circuit 201, a feedback control circuit 302, and an input ac voltage detection circuit 203; the feedback control circuit 302 includes a detection circuit 305, an error amplifier 301, and a first reference voltage generation circuit 306 composed of a controllable current source 303 and a resistor 304.
The detection circuit 305 is connected in series to an output capacitor CoutAnd the LED device to obtain a current sampling signal V representing the current driving current informationsense；
The error amplifier 301 has a first input terminal connected to the detection circuit 305 and a second input terminal receiving a second reference voltage Vref2And said drive voltage VLEDSum of said second reference voltage Vref2Characterizing a desired output current of the LED device; the error amplifier 301 is used for calculating the current sampling signal and a second reference voltage Vref2And a driving voltage VLEDAnd the error between the values to obtain an error control signal V indicative of the difference between the present drive current and the desired drive currenterror；
The error control signal VerrorIs input to the controllable current source 303 to control the output current of the controllable current source 303; the voltage of the output current of the controllable current source 303 over the resistor 304 is taken as the first reference voltage Vref1And with said drive voltage VLEDAfter superposition (FIG. 3), outputTo the first comparison circuit 201.
The working process is as follows:
when the absolute value V of the AC input voltageabGreater than the drive voltage VLEDAnd said first reference voltage Vref1When the voltage is summed, the first comparison circuit 201 controls the power switch SMOff, no output current; namely, when the input voltage is larger, no output current exists, and no power loss is generated;
when the absolute value V of the AC input voltageabGreater than the drive voltage VLEDBut less than said driving voltage VLEDAnd said first reference voltage Vref1When the voltage V is summed, the voltage V at the A end of the detection circuit is calculatedAVoltage V between B terminalBAnd a driving voltage VLEDError between the sum of (1);
when V isA＞VB+Vref2The error control signal V output by the error amplifier 301 is equal to or greater than the desired drive currenterrorDecreasing, the output current of the controllable current source 303 decreases accordingly, and thus the voltage drop over the resistor 304 decreases, i.e. the first reference voltage Vref1Decrease; time interval t of power switch capable of generating output current1Decreasing, thereby decreasing the average value of the output current, i.e. decreasing the drive current;
when V isA＜VB+Vref2The error control signal V output by the error amplifier 301 is equal to or greater than the desired drive currenterrorThe output current of the controllable current source 303 increases correspondingly, so that the voltage drop over the resistor 304 increases, i.e. the first reference voltage Vref1Increasing; time interval t of power switch capable of generating output current1Increasing, thereby increasing the average value of the output current, i.e. increasing the drive current; since the adjustable first reference voltage characterizes the difference between the current LED drive current and the desired drive current, the first reference voltage V is adjusted byref1Adjustment of value, guaranteed powerOutput current I of the switchoutThe average value of (d) matches the desired drive current.
With the LED driving circuit according to the present invention shown in fig. 3, the detection circuit 305 may be a resistor or other components or circuit modules that may have similar functions; power switch SMCan be a MOSFET transistor or other suitable switching tube; the first reference voltage generating circuit 306 may alternatively be any other suitable form of adjustable voltage generating circuit.
The high efficiency LED driving method according to the present invention will be described in detail with reference to the following embodiments.
Referring to fig. 4, a flow chart of a high efficiency LED driving method according to a preferred embodiment of the present invention is shown. In this embodiment, the LED driving method according to the present invention includes the steps of:
s401: receiving an alternating current input voltage, and detecting to obtain an absolute value of the alternating current input voltage;
s402: a power switch receives a DC bus voltage and generates a driving voltage and a driving current to drive an LED device;
the direct current bus voltage is obtained by rectifying the alternating current input voltage;
s403: generating a first reference voltage according to the present driving current and a desired driving current of the LED device;
s404: sampling a driving voltage of the LED device;
s405: comparing the absolute value of the AC input voltage with the sum of the drive voltage and the first reference voltage;
s406: turning off the power switch when the absolute value of the alternating current input voltage is greater than the sum of the driving voltage and a first reference voltage;
s407: when the absolute value of the alternating current input voltage is larger than the driving voltage and smaller than the sum of the driving voltage and a first reference voltage, the power switch is switched on to generate an output current;
the average value of the output current matches the desired drive current.
Wherein the adjusting of the first reference voltage comprises:
sampling the current driving current of the LED device;
calculating an error between the present drive current and the desired drive current to obtain an error control signal;
when the present drive current is less than the desired drive current, the error control signal adjusts the first reference voltage to increase the first reference voltage;
the error control signal adjusts the first reference voltage to decrease the first reference voltage when the present drive current is greater than the desired drive current.
Preferably, the step of detecting the present driving current comprises:
sampling the current driving current by using a detection circuit to obtain a current sampling signal;
calculating an error between the current sample signal and a sum of a second reference voltage characterizing a desired drive current and a present drive voltage to obtain the error control signal.
Optimally, the adjusting step of the first reference voltage comprises the following steps:
controlling a controllable current source according to the error control signal;
and charging a resistor by using the controllable current source, so that the voltage at two ends of the resistor is used as the first reference voltage.
Preferably, in order to prevent the conduction current of the power switch from being too large, the conduction current of the power switch may be limited.
Optimally, in order to reduce harmonic components in the on-current of the power switch, the waveform of the on-current of the power switch can be shaped.
By the LED driving method, when the direct current bus voltage, namely the input voltage, is small, the power switch outputs a certain output current within a certain time interval; the length of the time interval is adjusted to ensure that the average value of the output current is matched with the required driving current so as to meet the requirement of driving the LED device; and when the direct current bus voltage is larger, the power switch is turned off, so that the working efficiency is greatly improved compared with the LED driver adopting a linear regulator in the prior art.
In summary, according to the high-efficiency LED driving circuit and the driving method disclosed by the present invention, the corresponding output current is selectively output according to the numerical relationship between the input voltage and the driving voltage, while the maximum working efficiency is obtained, the main circuit structure is relatively simple, and the size and the cost are relatively well optimized.
The high efficiency LED driving circuit and driving method according to the preferred embodiment of the present invention are described in detail above, and those skilled in the art can deduce that other techniques or structures, circuit layouts, elements, etc. can be applied to the embodiments.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.
Claims (10)
1. A high-efficiency LED driving method for driving an LED device, comprising:
receiving an alternating current input voltage, and detecting to obtain an absolute value of the alternating current input voltage;
a power switch receives a direct current bus voltage and generates a driving voltage and a driving current to drive the LED device; the direct current bus voltage is obtained by rectifying the alternating current input voltage;
generating a variable first reference voltage according to a present driving current and a desired driving current of the LED device;
sampling a driving voltage of the LED device;
comparing the absolute value of the AC input voltage with the sum of the drive voltage and the first reference voltage;
turning off the power switch when the absolute value of the alternating current input voltage is greater than the sum of the driving voltage and a first reference voltage;
when the absolute value of the alternating current input voltage is larger than the driving voltage and smaller than the sum of the driving voltage and a first reference voltage, the power switch is switched on to generate an output current; the average value of the output current matches the desired drive current.
2. The LED driving method according to claim 1, further comprising:
sampling the current driving current of the LED device;
calculating an error between the present drive current and the desired drive current to obtain an error control signal;
when the present drive current is less than the desired drive current, the error control signal adjusts the first reference voltage to increase the first reference voltage;
the error control signal adjusts the first reference voltage to decrease the first reference voltage when the present drive current is greater than the desired drive current.
3. The LED driving method according to claim 2, further comprising:
controlling a controllable current source according to the error control signal;
and charging a resistor by using the controllable current source, so that the voltage at two ends of the resistor is used as the first reference voltage.
4. The LED driving method according to claim 1, further comprising limiting a conduction current of the power switch.
5. The LED driving method according to claim 1, further comprising performing a shaping operation on a waveform of an on-current of the power switch.
6. A high efficiency LED driving circuit includes a power switch for receiving an AC input voltage and generating a driving voltage and a driving current for driving an LED device, comprising,
the alternating voltage detection circuit is used for receiving the alternating input voltage and obtaining the absolute value of the alternating input voltage;
a feedback control circuit for generating a variable first reference voltage based on the received drive current and a desired drive current for the LED device;
the first comparison circuit is respectively connected with the alternating current voltage detection circuit and the feedback control circuit and is used for comparing the absolute value of the received alternating current input voltage with the sum of the first reference voltage and the driving voltage;
a first power end of the power switch receives a direct-current bus voltage, and the direct-current bus voltage is obtained by rectifying the alternating-current input voltage through a rectifier bridge; the second power end is connected to an output capacitor; the control end is connected to the first comparison circuit;
when the absolute value of the alternating-current input voltage is larger than the sum of the driving voltage and the first reference voltage, the first comparison circuit controls the power switch to be switched off;
when the absolute value of the alternating-current input voltage is larger than the driving voltage and smaller than the sum of the driving voltage and the first reference voltage, the first comparison circuit controls the power switch to be conducted, so that an output current is generated, and the average value of the output current is ensured to be matched with the expected driving current.
7. The LED driving circuit according to claim 6, wherein the feedback control circuit comprises a detection circuit, an error amplifier, a first reference voltage generation circuit; wherein,
the detection circuit is connected between an output capacitor and the LED device in series to sample the current driving current;
the error amplifier is used for calculating the error between the received current driving current and the expected driving current so as to obtain an error control signal;
the first reference voltage generating circuit correspondingly generates the changed first reference voltage according to the received error control signal, and inputs the changed first reference voltage and the driving voltage to the first comparison circuit after being superposed.
8. The LED driving circuit according to claim 7, wherein the first reference voltage generating circuit comprises a controllable current source and a resistor;
the error control signal is input to the controllable current source to control the output current of the controllable current source; the voltage of the output current of the controllable current source on a resistor is used as the first reference voltage.
9. The LED driving circuit of claim 6, further comprising a current limiting circuit connected between the power switch and the rectifier bridge to limit the conduction current of the power switch.
10. The LED driving circuit according to claim 6, further comprising a waveform shaping circuit connected between the power switch and the rectifier bridge to shape a waveform of the on-current of the power switch to reduce harmonic components thereof.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012100120983A CN102523666B (en) | 2012-01-16 | 2012-01-16 | High-efficiency LED (Light Emitting Diode) driving circuit and driving method thereof |
| US13/737,207 US8773041B2 (en) | 2012-01-16 | 2013-01-09 | High efficiency LED driver and driving method thereof |
| US14/274,910 US9078323B2 (en) | 2012-01-16 | 2014-05-12 | High efficiency LED driver and driving method thereof |
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| CN2012100120983A CN102523666B (en) | 2012-01-16 | 2012-01-16 | High-efficiency LED (Light Emitting Diode) driving circuit and driving method thereof |
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| CN102523666B CN102523666B (en) | 2013-08-14 |
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| CN (1) | CN102523666B (en) |
Cited By (5)
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| CN104660019A (en) * | 2015-01-16 | 2015-05-27 | 矽力杰半导体技术(杭州)有限公司 | Multi-phase parallel converter and control method thereof |
| CN108156688A (en) * | 2016-12-05 | 2018-06-12 | 安葳科技股份有限公司 | High-efficiency linear L ED driving circuit |
| CN108391338A (en) * | 2017-02-03 | 2018-08-10 | 半导体元件工业有限责任公司 | The direct AC drive control devices integrated circuit of light emitting diode |
| CN107087328A (en) * | 2017-06-08 | 2017-08-22 | 杭州乐图光电科技有限公司 | Led drive circuit |
| CN107087328B (en) * | 2017-06-08 | 2023-12-05 | 安徽乐图电子科技股份有限公司 | LED driving circuit |
| CN110690813A (en) * | 2019-09-12 | 2020-01-14 | 珠海格力电器股份有限公司 | Capacitor charging control method and device based on switch control and converter |
Also Published As
| Publication number | Publication date |
|---|---|
| US8773041B2 (en) | 2014-07-08 |
| CN102523666B (en) | 2013-08-14 |
| US9078323B2 (en) | 2015-07-07 |
| US20140246985A1 (en) | 2014-09-04 |
| US20130181626A1 (en) | 2013-07-18 |
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